61 lines
2.2 KiB
Diff
61 lines
2.2 KiB
Diff
|
From f6613104a37c1d43cb50fd619afccba370db47a0 Mon Sep 17 00:00:00 2001
|
||
|
|
From: Joel Colledge <joel.colledge@linbit.com>
|
||
|
|
Date: Tue, 20 Aug 2024 12:28:09 +0100
|
||
|
|
Subject: [PATCH 02/32] drbd: inherit history UUIDs from sync source when
|
||
|
|
resync finishes
|
||
|
|
|
||
|
|
This prevents unexpected "unrelated data" or "split-brain" situations
|
||
|
|
from occurring later. For example with nodes A, B and C:
|
||
|
|
* A diskless, B, C with disk, all connected, on UUID X
|
||
|
|
* Down B
|
||
|
|
* Write on C, new UUID Y generated
|
||
|
|
* Add disk on A, resyncs from C
|
||
|
|
* Down C
|
||
|
|
* Up B, connects to A, should resync from A
|
||
|
|
|
||
|
|
Without this change, "unrelated data" or "split-brain" occurs between A
|
||
|
|
and B.
|
||
|
|
Node A has current UUID Y, but knows nothing about X.
|
||
|
|
Node B has current UUID X, but knows nothing about Y.
|
||
|
|
|
||
|
|
This scenario is also possible with "quorum majority".
|
||
|
|
|
||
|
|
Fix this by adding the history and bitmap UUIDs from the sync source
|
||
|
|
into the history on the sync target when a resync finishes. In the above
|
||
|
|
scenario, this adds the UUID X into the history on A and so has the
|
||
|
|
effect that a full sync from A to B occurs in the final step.
|
||
|
|
---
|
||
|
|
drbd/drbd_main.c | 11 +++++++++++
|
||
|
|
1 file changed, 11 insertions(+)
|
||
|
|
|
||
|
|
diff --git a/drbd/drbd_main.c b/drbd/drbd_main.c
|
||
|
|
index 7968be7c4c3f..862438885f35 100644
|
||
|
|
--- a/drbd/drbd_main.c
|
||
|
|
+++ b/drbd/drbd_main.c
|
||
|
|
@@ -5030,11 +5030,22 @@ u64 drbd_uuid_resync_finished(struct drbd_peer_device *peer_device) __must_hold(
|
||
|
|
{
|
||
|
|
struct drbd_device *device = peer_device->device;
|
||
|
|
unsigned long flags;
|
||
|
|
+ int i;
|
||
|
|
u64 ss_nz_bm; /* sync_source has non zero bitmap for. expressed as nodemask */
|
||
|
|
u64 pwcu; /* peers with current uuid */
|
||
|
|
u64 newer;
|
||
|
|
|
||
|
|
spin_lock_irqsave(&device->ldev->md.uuid_lock, flags);
|
||
|
|
+ // Inherit history from the sync source
|
||
|
|
+ for (i = 0; i < ARRAY_SIZE(peer_device->history_uuids); i++)
|
||
|
|
+ _drbd_uuid_push_history(device, peer_device->history_uuids[i] & ~UUID_PRIMARY);
|
||
|
|
+
|
||
|
|
+ // Inherit history in bitmap UUIDs from the sync source
|
||
|
|
+ for (i = 0; i < DRBD_PEERS_MAX; i++)
|
||
|
|
+ if (peer_device->bitmap_uuids[i] != -1)
|
||
|
|
+ _drbd_uuid_push_history(device,
|
||
|
|
+ peer_device->bitmap_uuids[i] & ~UUID_PRIMARY);
|
||
|
|
+
|
||
|
|
ss_nz_bm = __test_bitmap_slots_of_peer(peer_device);
|
||
|
|
pwcu = peers_with_current_uuid(device, peer_device->current_uuid);
|
||
|
|
|
||
|
|
--
|
||
|
|
2.35.3
|
||
|
|
|